Pardon the CO 'humour',but a couple of questions, are you an elite with CO, and if so what level, or are you using miles to upgrade? I wouldn't count on just an operational upgrade ever with CO on that route.
Assuming you are some sort of elite, (even Silver) I'd say your chances were very very good. Unless they've got some sort of convention going out to Chicago or a tour group (tours to Chicago in Jan???)-- it appears that flight will be pretty empty. If you haven't been EUA'd yet, give them a call.
If you are an elite, I wouldn't waste miles since you'll most certainly get the upgrade.
I do that route frequently, and as a Platinum I've never NOT been upgraded---always at the 72 hour point.